Polyembryony, Biology

Assignment Help:

Polyembryony

Presence of more than one embryo in a seed is termed polyembryony. The phenomenon, first discovered in orange seeds by Leeuwenhoek (1719), attracted considerable attention because of its potential for application in and horticulture. Polyembryony is broadly classified into simple and multiple, depending on whether the supernumerary arises in one or more embryo sacs in the ovule. Simple polyembryony may be sexual or asexual. In sexual polyembryony embryos may originate from the fertilized egg and synergids, or by budding or cleavage of the polyembryony cells or suspensor of the zygotic embryo.

Asexual embryos are produced within the embryo sac without fertilization. Embryos may also originate from diploid nucellar or integumentary cells of the ode and grow into the embryo sac. These embryos are termed adventive or sporophytic. Multiple polyembryonies involve production of accessory embryos from two or more embryo sacs in the same ovule. For example, in the sea Island cotton, Gossypium barbadense, fertilization of egg in one embryo sac stimulates the induction of embryo from an unfertilized egg in the adjacent embryo sac within the same ovule. Thus, diploid-haploid twin embryos are produced in the seed.


Related Discussions:- Polyembryony

Orthopedics, 1. List alternative therapies for musculoskeletal problems. ...

1. List alternative therapies for musculoskeletal problems. 2. What is a xyrospasm? What is the Greek derivative of the word? 3. Name and describe the three types of varus con

Explain ventilation and niv, Explain Ventilation (NIV)? This refers to ...

Explain Ventilation (NIV)? This refers to the use of mechanical ventilatory support without the use of an endotracheal tube. NIV may be by the application of a continuous posit

Bovine ephemeral fever, B o v i ne ephemeral fever Ephemeral fever ...

B o v i ne ephemeral fever Ephemeral fever is commonly known as 'three-day sickness'. It affects mainly cattle and occasionally sheep in India. Causative agent is a mosquit

How the respiratory system in aquatic molluscs characterized, Q. How is the...

Q. How is the respiratory system in aquatic molluscs characterized? What adaptive respiratory structure do terrestrial molluscs present? In terrestrial molluscs the rich vascul

What do you mean by amphibians of the plant world, Q. Why can the bryophyte...

Q. Why can the bryophytes be considered the "amphibians of the plant world"? Like adult amphibians, the bryophytes live in the terrestrial environment but they depend on water

Prophase, Prophase This is the first and longest phase of mitosis .At i...

Prophase This is the first and longest phase of mitosis .At its beginning  all  10 nm segments   of chromatids (= chromonemata)  of the  duplicated  chromatin fibres of interph

Health promotion for the general population, Q. Health Promotion for the Ge...

Q. Health Promotion for the General Population? Targeted to have a healthy, risk free population and involves development of an effective communication strategy to modify indiv

Palaeontological evidence of evolution, EVIDENCES OF EVOLUTION - The ev...

EVIDENCES OF EVOLUTION - The evidences of organic evolution derived from many lines of study indicate that present day forms have arisen by gradual changes from pre existing fo

What does fungus looks like, Q. What does this fungus looks like? Ans...

Q. What does this fungus looks like? Ans. The important characteristic features of aflatoxicosis are jaundice, cirrhosis. Long term exposure to aflatoxins could lead to

Nursing responsibilities while administering immunization, NURSING RESPONSI...

NURSING RESPONSIBILITIES WHILE ADMINISTERING IMMUNIZATION Use one sterile syringe and needle for each injection.  Use only the diluent supplied along with measles and

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd